I am writing a brief report comparing automated assembly methods for Through-Hole and Surface Mount technology. To help me reach a solid conclusion I have broken the report down to eight key pointsDuring the manual assembly and soldering of surface mount technology(SMT) we come across many problems, this is in part due to being assembled manually and will not always be done correctly. For example, An overheated joint. This is when the solder hasn’t flowed properly and the residue of the burnt flux has stuck to the board. Furthermore, when the solder has been removed for some reason but has done so too early and hasn’t had the time to melt properly we get a cold joint which is unreliable as the bonds are poor and cracks can develop over time. Moreover, simple things like a solder starved joint were the joint hasn’t been given enough solder to stick well and causes loose connections or excessive use of solder which can block our sight of how well the solder is connected making us unaware of how well the connection is. A disrupted joint can easily occur when the solder has moved while it is becoming solid. Finally, insufficient wetting can happen when the solder has wetted the connections well but hasn’t connected to the board enough, this can be caused by not applying heat to the pad as well as the solder.During the transport of a circuit board it is very important that a level of caution is used as even the smallest amount of static electricity can destroy a board and too much pressure on a small component can damage it. Some precautions to take when transporting circuit boards within an assembly facility are; keep the circuit board in an anti-static bag so no static electricity can get to the board causing potential damage. Make sure the workplace the boards are kept in has a high humidity as electricity tends to increase in dry air. Place the circuit board into the right area of the computer using only as much pressure is needed to put it into the module correctly. Don’t force the board into the module and be careful not to bend it. Do not keep any plastic near the circuit boards, as plastic can create a static charge. Before even touching a circuit board always have rubber-soled boots on to stop a build-up of static electricity. This too can cause damage to the board. Furthermore, discharge any electricity your body may have by touching a piece of metal for a few seconds, this will also stop unneeded static electricity from reaching the board. Finally, make sure to have gloves on before removing the circuit board from the anti-static bag (carefully do so) keeping a point of the board still in contact to the bag, leave the circuit board on the bag until you need to start installing the components.During the production of printed circuit boards(PCB) Solder paste is a material used to connect components to pads on the boards. You can also solder through hole pin in paste components by printing solder paste in or over the holes. First of all, the paste immobilises components still by being sticky, it is then heated as well as the rest of the board, melting the paste and forming a mechanical bond as well as an electrical connection. The three main kinds of solder paste deposition are; Step stencil, Dispensing and Jetting. Step stencils are stencils varied by material thickness and is useful as in more time the components used will get smaller. Step stencils have the possibility of soldering all chip component types into cavities which goes down to 01005 (0402) sized chips. Step stencils are also able to accommodate different depth cavities, which is limited to the stencil being manufactured. Furthermore, it has a low cycle time as standard screen printer is used. However, more work is required to support different depths and apertures in the same stencil. Dispensing is the transfer of precise and uniform adhesive dot shape and height at varying volumes onto the PCB solder mask surface which can accommodate different depth cavities without any restrictions. Finally, Jetting is the process in which fluid is ejected rapidly through a nozzle. Jetting can achieve IPC 610 Class 3 solder joints, which includes 01005 (0402) chip size.Pick and place machines are a piece of equipment used in the manufacturing of printed circuit boards. Pick and place machine are machines which are used to place surface-mount devices (SMDs) onto a printed circuit board (PCB). They are used for high speed, high precision placing of broad range of electronic components onto the PCBs which are in turn used in computers, etc. Several sub-systems work together to pick up and correctly place the components onto the PCB. These systems normally use suction cups, attached to a plotter-like device to allow the cup to be accurately manipulated in three dimensions. The machine has a component feeder which supplies components in tape reels that are loaded onto feeders on a conveyer belt, then the PCB is clamped, and the nozzles pick up individual components from the feeders, rotate them to the correct orientation and then place them on the appropriate pads on the PCB with high precision. It then photographs the PCB to inspect everything is in place.Reflow soldering is a process in which a solder paste is used to temporarily join one or more components to their contact pads, after which the assembly is then put into controlled heat, which melts the solder, permanently connecting the joint. Heating may be accomplished by passing the assembly through a reflow oven or by soldering individual joints with a hot air pencil. It’s is the most used method of connecting Surface Mount components(SMC) to a circuit board. The objective of the reflow process is to melt the solder and heat the adjoining surfaces, without overheating and damaging the electrical components. In the conventional reflow soldering process, there are usually four stages, called zones; Preheat zone, thermal soak zone, reflow zone and cooling zone.Cleaners are used to remove particulates from PCBs. The equipment is always evolving as components are always progressing into smaller components, so cleaners have to be upgraded to keep up with the newer smaller components. Moreover, cleaners are used in the SMT process at the beginning to ensure clean boards are being used so the screen printer can print more accurately. There are two types of PCB cleaners; Adhesive roller type cleaner and Bruch type cleaners. Flux is a chemical cleaning agent. It is used in all sorts of metallurgy, for example; wave soldering. Flux as a cleaning agent helps soldering, by removing oxidation from the metals to be joined. During the soldering process the main objective of flux is to prevent oxidation of the base and filler materials. Additionally, flux is a substance, which is almost useless at room temperature, but when the heat rises the flux starts to work, preventing the formation of metal oxides. Also, flux grants solder the ability to flow easily on the piece rather than forming beads, as it would otherwise. It is the main purpose of a flux in joining processes is usually acting as a boundary for air by coating the hot surface, stopping oxidation from happening and dissolving of the oxides on the surface, which allows wetting by molten metal.Lead forming devices usually start with unformed leads. Their main purpose is to trim and shape leads without harming the component, altering the leads or changing coplanarity needs decisive equipment and careful engineering. Furthermore, both manual and pneumatic presses can be used to form leads on flat packs, multichip modules and other packages. Tooling can be changed. Moreover, dedicated tooling might be needed for medium volume production with expensive components. At the start of the lead forming process engineers need to determine dies or presses for lead forming, they should then firstly determine the values and resistances of five component dimensions: how long the component is from lead tip to lead tip. Also, the distance from the top of the board to the bottom of the component, the length of the lead foot. The thickness of the leads and the shoulder length, or the length of the lead from the component body to the first bend in the lead.Wave soldering is a big soldering process used in the manufacture of printed circuit boards. The circuit board is passed over a slide of hot solder in which a pump produces an upwelling of solder that looks like a standing wave. As the circuit board makes contact with this wave, the components become soldered to the board. Several different pieces of equipment are used in the wave soldering process such as; A conveyor moves the PCB through the different zones, a slide of molten solder (made up with a mixture of metals) is used in the soldering process, a pump that produces the actual wave, the sprayer for the flux, which is mainly used to clean components being used and to help with oxide layers that could have formed. Moreover, a piece of equipment which is used to speed up the soldering process called the preheating pad. Finally, the PCBs are then cooled down and need to be allowed to cool in a precise time. if the PCB is allowed to cool too slowly, then the PCB can become weak and some components may be damaged by heat. Furthermore, if they are cooled too fast, then the PCB can become corrupt and the solder can be compromised. On the other hand, The PCB is usually cooled by either a fine water spray or air cooled to decrease the amount of damage to the board.I feel that I have compared automated assembly methods for Through-Hole and Surface Mount technology successfully with the help of my eight key points.